Textured base materials or products from certain carboxyalkyl ethers of polygalactomannans and process of preparing same

ABSTRACT

A FIBROUS PRODUCT IS PREPARED BY MIXING A FLUID, AQUEOUS SOLUTION OF CERTAIN CARBOXYALKYL ETHERS OF POLYGALACTOMANNAS WITH A SECOND AQUEOUS SOLUTION CONTAINING CALCIUM IONS, SAID MIXING BEING SUFFICIENT TO RUPTURE THE FORMING SAC-LIKE PRECIPITATES TO YIELD THE FIBROUS PRODUCT. THE SAID PRODUCT IS USEFUL AS A STRUCTURING AGENT FOR VARIOUS FOODS, SUPPLYING SUCH STRUCTURE WITHOUT CALORIE CONTRIBUTION.

United States Patent Ofice 3,782,962 Patented Jan. 1, 1974 TEXTURED BASE MATERIALS OR PRODUCTS FROM CERTAIN CARBOXYALKYL ETHERS OF POLYGALACTOMANNANS AND PROCESS OF PREPARING SAME Joseph D. Mullen, Golden Valley, and Mary P. Nivens,

New Hope, Minn., assignors to General Mills, Inc. No Drawing. Filed Mar. 7, 1972, Ser. No. 232,604

Int. Cl. A23] 1/00 US. Cl. 426--70 11 Claims ABSTRACT OF THE DISCLOSURE A fibrous product is prepared by mixing a fluid, aqueous solution of certain carboxyalkyl ethers of polygalactomannans with a second aqueous solution containing calcium ions, said mixing being suflicient to rupture the forming sac-like precipitates to yield the fibrous product. The said product is useful as a structuring agent for various foods, supplying such structure without calorie contribution.

The present invention relates to the production of textured products especially useful in the preparation of foods of various types. More particularly, it relates to the preparation of new fibrous base materials from certain carboxyalkyl ethers of polygalactomannas.

It has recently been discovered that carboxyalkyl ethers of polygalactomannans having a D.S. of about 0.6 can be mixed with small amounts of calcium salt or materials yielding calcium ions, thereby greatly increasing the effectiveness of said carboxyalkyl ethers as thickening agents. It was also discovered that the described high D.S. carboxyalkyl ethers of the galactomannan gums could be used to form fibers by spinning techniques-4c. forcing of a relatively dilute solution or dispersion of the said carboxyalkyl ether into an aqueous coagulating bath containing Ca++ ions to form monofilaments. Such monofilaments were found useful in the construction of meat analogs.

We have now discovered that a highly useful fibrous product can be prepared from the high D.S. carboxyalkyl ethers of polygalactomannans by. a unique process having substantial advantages over the spinning technique referred to above. Thus, when a solution of the said carboxyalkyl ether is mixed with an aqueous solution containing excess Ca ions, large sac-like precipitates are formed. We have found that a fibrous product is obtained if the two solutions are subjected to mixing action suflicient to rupture or sever the forming sac-like precipitates. The resulting fibrous-gel mass resembles crab meat in appearance and eating quality.

Our process affords a number of advantages. Thus as compared to the previous spinning process, our process requires no spinnerettes and no fiber orienting techniques involving take-up reels to stretch the tow of fibers. Additionally, in the process of this invention gelled fiber formation takes place throughout the bulk of the carbohydrate solution rather than at the relatively small area of a spinnerette face. Accordingly, very large quantities of materials can be processed since only the sizes of the tanks and mixing devices are limiting as compared to the number and throughput of spinnerettes.

Further, production of fibrous base products by our process can involve simultaneous purification and texturization of the crude carboxyalkyl ethers. In this respect, when a polygalactomannan such as guar gum is converted to the carboxyalkyl ether such as by reaction with sodium chloroacetate in the presence of NaOH, a large amount of NaCl and sodium glycolate byproducts are formed. Reactions to make a 1.2 D.S. product, for instance, yeild a mixture of about 40% by weight of the ether and 60% by weight of the inorganic by-products. In our process, the ether and the inorganic by-products are solubilized in Water and the ether removed as the calcium salt in the form of the fibrous material. Most of the inorganic by-products remain soluble and are separated such as by being decanted off in the water. Any entrapped inorganic by-products can then be removed when the fibrous material is slurried in water during optional washing steps. Accordingly, our process can eliminate alcohol extractions, rewetting and vacuum drying steps associated with the obtaining of a purified starting material by one of the procedures described hereinbelow.

The product of the present invention has a texture which appears more meat-like than that produced by conventional spinning techniques. It is probably more meatlike because there is a lack of specific orientation and the fibrous mass has a combined fiber-gel structure which gives a distinct meat or seafood-like eating quality due to entrapped liquid. The water content of the fibrous product after separation from the aqueous medium is commonly 8S% by weight although product can be made with higher or lower moisture levels.

The starting materials used in our process are carboxyalkyl ethers of polygalactomannans having a D.S. of at least about 0.6. By D.S. (degree of substitution) as used herein is meant the average substitution of carboxyalkyl ether groups per anhydro sugar unit. In guar gum, for example, the basic unit of the polymer is comprised of two mannose units with a glycosidic linkage and a galactose unit attached to one of the hydroxyls of the mannose units. On the average, each of the sugar units has three available hydroxyl sites. A D.S. of 3.0 would mean that all of the available hydroxyl sites had reacted to form carboxylalkyl ether groups. A D.S. of 1.0 would mean that onethird of the available hydroxyls had reacted. The D.S. of the starting materials of the present invention thus have a D.S. of at least about 0.6 and preferably up to about 2.0. Products having D.Ss in the range of about 0.9 to 1.6 are especially preferred.

The starting carboxyalkyl ethers can be prepared in a number of ways from polygalactomannans. The latter term as used herein includes the general class of polysaccharides containing both galactose and mannose units. The polygalactomaunans are usually found in the endosperm sections of leguminous seeds such as guar, locust bean, honey locust, fiametree and Cassia occidentalis. Because of ready availability, guar and locust bean gums are the preferred polygalactomannans.

One preferred method of preparing the carboxyalkyl ether starting materials is to first treat the polygalactomannan with a halo fatty acid or alkali metal salt thereof followed by treatment with an alkali metal hydroxide reaction initiator. The resulting product will be an alkali metal salt of the carboxyalkyl polygalactomannan. In such process, the polygalactomannan is first dry mixed with a dry powder halo fatty acid or salt of a halo fatty acid. Suitable halo fatty acid reactants are those having 2 to 4 carbon atoms in the fatty chain. Representative specific halo fatty acid reactants are chloroacetic acid, achloropropionic acid and ehlorobutyric acid and the alkali metal salts thereof. It is especially preferred to use sodium chloroacetate.

After the dry mixing of polygalactomannan and the halo fatty acid reactant, an aqueous solution of an alkali metal hydroxide reaction initiator, preferably sodium hydroxide, is added as a solution of up to 73% by weight concentration. The addition of the hydroxide solution is done by increments over a period of ten minutes to one hour or so. After the addition is complete, the mixture is mixed at room temperature for ten minutes to one hour and then heated for a period of time. The temperature and time are variable such as at room temperature for one day but preferably 50-60 C. for /2 to 3 hours. If too much water is used, the product fuses to a viscous dough which cannot be easily handled. The product can be dried until the moisture content is less than and then ground. The product can then be extracted with an aqueous 80/20-methanol/water solution by mixing in a blender under moderate stirring at 30 C. for 20 minutes. Acetic acid can be added to the blender to neutralize the product. If desired the product can then be filtered and dried. The purification step can be repeated as desired to further remove by-product salts. As indicated hereinabove the crude unpurified sodium salt of the carboxyalkyl ether can be used directly in the process of the present invention.

Where a high purity starting material is desired (i.e. such as when a high degree of whiteness is desired in the fibrous product), it is preferred to carry out the reaction of the polygalactomannan and the halo fatty acid reactant (in the presentce of an alkali metal hydroxide initiator) in an alcohol-water solvent slurry. The use of such a slurry provides a relatively uniform fluid which eliminates agitation and heat transfer problems to a great degree. Because the galactomannan gum is maintained in a solid suspended state throughout the reaction period, the resulting carboxyalkyl ether is in substantially the same physical state as the gum starting material. This finely divided physical state leads to more uniform substitution and greatly enhances extraction of salts therefrom.

Suitable alcohols for the above process are monohydric alcohols of 2 to 4 carbon atoms. The preferred such alcohol is isopropyl alcohol. Other of these alcohols such as ethanol, n-propanol and tertiary butanol are also useful but are more costly than isopropyl alcohol. Suflicient water is included in the solvent -system to at least slightly swell the polyaglactomannan but too much water will swell the gum so much that filtration will be diflicult. It is thus preferred to use solvent systems containing up to about by weight water and more preferably from about 15 to 40% by weight water. The alcohol-water solvent system will be present in an amount suflicient to form a fluid slurry of the reactants. Preferably, the alcohol-water solvent system will be used in an amount of about 3 to 10 times the weight of the polygalactomannan.

The reaction time is not critical in this slurry method although it is desirable to complete the reaction in a reasonable periodi.e. in less than about five hours and more preferably in /2 to 2 hours. Additionally, at the lower water levels, the reaction should be terminated prior to the point where the pH of the reaction mixture drops much below 7.0. It is also preferred to carry out the reaction at temperatures of to 80 C. Temperatures much above 80 C. should ordinarily be avoided because of the possibility of excessive alkali degradation of the polygalactomannan. At the completion of the reaction period, the reaction mixture may be filtered and dried. However, it is optional to further purify the product by washing with aqueous methanol to remove salts (i.e. NaCl, sodium glycolate and the like). The washed product can then be dried.

In both of the above-described proceduers, the defined halo fatty acid reactant is used in an amount suflicient to yield the carboxyalkyl ether product having the desired D.S. of at least about 0.6, and preferably from about 0.6 to 2.0. Using the preferred sodium chloroacetate and guar gum, the amounts of reactants can be expressed as from about 0.4 to 3.5 equivalents of the former to 100 grams of the latter. In terms of parts by weight, about to 400 and preferably 90 to 200 parts of sodium chloroacetate would be used for each 100 parts of the guar flour.

The alkali metal hydroxide functions as a reaction initiator by reaction with the available hydroxyl groups of the polygalactomannan. The resulting alcoholate groups are then capable of reaction with the halo fatty acid reactant. As such, it is preferred to use an excess of the alkali metal hydroxide but, in any event, it is desirable to use at least about the same equivalents thereof per 100 grams of the polygalactomannan as the equivalents of the halo fatty acid reactant. In parts by weight, it is preferred, for example, to use 20 to 140 parts sodium hydroxide to 100 parts guar gum.

In accordance with the present invention, a fluid solution of the described high D.S. carboxyalkyl ethers of the polygalactomannans is mixed with an aqueous solution containing excess Ca ions, such mixing being suflicient to rupture or sever the forming sac-like precipitates thus yielding the fibrous gel mass. The concentration of the high D.S. carboxyalkyl ether in the aqueous solution is suflicient to yield the desired fibrous product. Preferably, the said ether will be added to water in an amount of about 0.5 to 5.0% by weight. At concentrations much above 5.0%, the viscosity is quite high and eflicient mixing becomes diflicult. It is here noted that the term solution is used. However, the high D.S. carboxyalkyl ether may actually be colloidally dispersed in whole or part in the water and the term solution is intended to cover such colloidal dispersions.

The formation of the solution of the carboxyalkyl ether can be assisted by heating. Such heating appears to aid in the formation of a more fibrous product which may be due to the obtaining of a more uniform solution or colloidal dispersion. Autoclaving of the starting solutions for 5, 20 and 30 minutes gave fibrous products with 87, and 65% water content, respectively. The fibrous character of the product increased as the water content decreased.

The Ca++ containing aqueous solution is obtained by dissolving an ionizable calcium salt in water. Representative salts are calcium chloride, calcium acetate, calcium lactate and the like. Calcium chloride is preferred. The said aqueous solution contains Ca++ ions at least in excess of the equivalents of the carboxyalkyl ether of the polygalactomannan, said equivalents being based on the carboxyalkyl ether groups. While large excesses of Ca can be usedi.e. five or more equivalents per equivalent of carboxyalkyl ether-an especially preferred ratio 18 about three equivalents Ca1++ per one equivalent of carboxyalkyl ether. Lower excesses require somewhat longer reaction times whereas larger excesses do not improve the fibrous product appreciably in comparison to the costs involved and the efforts required to remove, if desired, the unused Ca++ ions.

As indicated, upon mixing of the high D.S. carboxyalkyl ether solution with the Ca containing aqueous solution, large somewhat tear drop shaped sacs of precipitate are formed. In the absence of mixing suflicient to rupture said sacs, the same are virtually totally gel-like in character. However, according to the present invention, the contacting solutions are subjected to suflicient mixing action to rupture or sever the sacs thus forming the fibrous product. While We do not fully understand the reasons for the formation of a fibrous product, it is theorized that the mixing action ruptures the sacs and causes (1) new precipitate formation and/or (2) shredding of the saclike precipitate and elongation of the shredded pieces.

While a ribbon blender was used to produce the mixing action in the examples to follow, any of a variety of other mixing devices can be used including simple hand mixing as with a fork held in the hands. Any device and mixing action which ruptures the forming sac-like precipitates and causes the formation of elongated'shreds thereof is sufiicient for the purposes of the present invention. Other representative commercially available mixers are Baker-Perkins and Rietz mixers and paddle mixers utilizing high speed stirring blades.

The fibrous product is preferably prepared when the two solutions being mixed are at room temperature (i.e. about 25 C.). However, higher temperatures such as up to about C. can be used. As the temperature of the reaction solutions is increased, the fibrous nature of the product is reduced somewhat and higher gel character is evident. Accordingly, room temperature is preferred for economic and practical reasons as well as for the obtaining of optimum fibrous character in the product. Lower temperatures down to the point of freezing can be used with no attendant advantages but with increased costs due to needed refrigeration or cooling equipment.

Subsequent to the formation of the fibrous product, excess aqueous reaction media can be removed by any conventional means including decantation, filtration, screening, and the like. In the absence of dehydration, the product will normally contain about 75 to 95% by Weight water following separation from the excess aqueous reaction medium. Product with about 85% by weight water is preferred for many applications. The product can also be dehydrated by conventional techniques but is preferably formulated into finished foods from the wet stage. Additionally, the product can be passed through serrated rolls. Such optional further treatment breaks up some gel-like portions and facilitates washing. Of course, washing steps can be used where desired to remove by-product salts and the like and excess Ca ions.

The fibrous product can be formulated into a variety of foods wherein a fibrous texture is desired. Thus various flavoring agents can be added as well as any other food addends such as coloring, spices, binders and the like. Since the fibrous calcium salts of the carboxyalkyl ethers of the present invention are essentially non-assimilable by the human body, the resulting textured foods have lower caloric value than their natural counterparts such as meats, fish, poultry and the like. The fibrous products of the invention can also be used in combination with natural pieces of meat, fish and the like thus serving as non-caloric extenders thereof.

The following examples serve to illustrate preferred embodiments of the invention without being limiting.

EXAMPLE I (Part 1) Preparation of high D.S. sodium carboxymethyl guar Thirty-nine pounds of isopropyl alcohol and 18.5 lbs. of distilled water were charged to a 30-gallon round bottom reaction flask. To this mixture was added lbs. of guar flour with mixing until the suspension was uniform. Over a period of ten minutes, 11.2 lbs. of 50% by weight aqueous NaOH was added to the reaction mixture (heating occurs as the base and aqueous alcohol mix). Mixing was continued for an additional ten minutes and then 20 lbs. of sodium chloroacetate was added over a -minute period (with mixing). The temperature was allowed to rise to 58-60 C. and such temperature was maintained for one and one-half hours while the reaction mixture was being continuously mixed throughout. Excess solvent was removed by centrifugation to yield sodium carboxymethyl guar having a D.S. of 1.1.

(Part 2) Preparation of fibrous product Thirteen and lb. of the sodium carboxymethyl guar prepared above were dissolved in 333 lbs. (40 gallons) of tap water at 25 C. by stirring in a jacketed stainless steel slurry tank. This approximately 4% by weight solution was raised over a period of one hour to 9095 C. with stirring. It was held at this temperature for 30 minutes and then cooled to 30 C. by passing over a heat exchanger. About 30 minutes were required for the total charge to be cooled and transferred to a 500-pound ribbon blender. An aqueous 2 M CaCl solution (4.75 gallons) was poured into the solution while the ribbon blender was being operated at 38 r.p.m. The blender was operated for an additional 15 minutes and the resulting fibrous gel-like product was collected by screening and passed between serrated rolls separated by about 0.042 inch. The fibrous product resembled crab meat in texture.

EXAMPLE II Example I, Part 2 is repeated except that the fibrous product is held overnight in the aqueous reaction medium to toughen the product. The fibrous product is then washed in the ribbon blender by mixing about 25-50 lbs. of the rolled fiber with 400 lbs. of cold tap water for 5-15 minutes. Washing is repeated until the product is essentially free of CaCl taste. The product after collection by screen ing can be stored at refrigerator temperatures or frozen for long term storage.

EXAMPLE 1111 Ten pounds of guar flour were blended with 20.0 lbs. of finely divided sodium chloroacetate in a Littleford mixer (jacketed reactor fitted with scraping and cutting blades). Over a period of 30 minutes a cooled solution (10 C.). of 5.6 lbs. sodium hydroxide dissolved in 8.5 lbs. of water was added to the guar-sodium chloroacetate blend. The reactor was sealed and the temperature brought to 38 C. The temperature was held between 49 and 60 C. for 30 minutes while the reactants were being mixed. After cooling, a 4% by weight solution of the yellow granular sodium carboxymethyl ether of guar (D.S. of 1.1) was made in a SO-gallon slurry tank and neutralized with 6 N HCl. The procedure of Part 2 of Example I was followed with such 4% by weight solution to yield a fibrous product of the same type as obtained in Example I (the product was not quite as white as the product of Example I).

EXAMPLE IV A crab meat-like salad was prepared by mixing 60 g. of the fibrous product as prepared in Example I with 55 g. salad dressing, 15 g. milk, 12.5 g. chili sauce, 40 g. diced celery, 3.0 g. diced scallion, 3.5 g. diced pimento and 0.5 g. imitation crab flavor. The salad Was very much like the same dish prepared using natural crab meat.

EXAMPLE V A breakfast sausage was prepared by mixing the following:

,Percent by weight Fibrous product of Examples I or III 22.2 Cooked ground pork sausage 48.5 Pork sausage seasoning 2.5 Sodium caseinate 0.7 Water 22.9 Cereal crumbs 3.2

The product when fried was very similar to the corresponding sausage made solely from ground pork. However, it had approximately 40% less calories.

EXAMPLE VI A Wiener-like product was made from the following ingredients:

Percent by weight Fibrous product as prepared in Examples I or The resulting mixture was stuffed into casings. Again the product was very similar to the natural all meat product but had approximately 50% fewer calories.

EXAMPLE VII A chicken loaf type product was prepared by mixing the following ingredients and shaping the same in a rectangular loaf pan with a spring loaded cover followed by heating in boiling water for two hours:

Percent by weight Fibrous product as prepared in Examples I or Again the product was much like its natural counterpart but with approximately 50% fewer calories.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A process for preparin a fibrous product which consists essentially of forming a fluid aqueous solution of a carboxyalkyl ether of a polygalactomannan having a D.S. of at least about 0.6 and wherein the alkyl group contains 1 to 3 carbon atoms and then mixing the said solution with a second aqueous solution containing calcium ions in excess of the equivalents of carboxyalkyl groups in the first solution, said mixing being sufiicient to rupture the forming sac-like precipitates and cause formation of elongated shreds thereof to yield the fibrous product.

2. The process of claim 1 wherein the polygalactomannan is guar and the D.S. of the carboxyalkyl ether is from about 0.6 to 2.0.

3. The process of claim 2 wherein the alkyl group is methyl and the carboxymethyl ether is present as the sodium salt.

4. The process of claim 3 where the first solution contains from about 0.5 to 5.0% by weight of the sodium carboxymethyl ether of guar.

5. The process of claim 4 wherein the calcium ions in the second solution are derived from calcium chloride.

6. The process of claim 5 wherein the calcium ions are present in the mixed solutions in an amount of about three equivalents per equivalent of sodium carboxymethyl ether of guar.

7. The process of claim 1 wherein the solution of the carboxyalkyl ether is heated prior to being mixed with the calcium ion containing solution.

8. The process of claim 1 wherein the mixing is carried out at room temperature.

9. The process of claim 1 wherein the fibrous product is separated from the excess aqueous reaction medium and then washed to remove excess calcium ions and byproduct salts.

10. The fibrous product prepared by the process of claim 1. i

11. A structured food comprising the fibrous product of claim 10 and one or more food addends.

References Cited UNITED STATES PATENTS 3,093,483 6/1963 Ishler et al. 99131 3,627,536 12/1971 Arima et a1. 99--14 X 3,674,500 7/1972 Naqasawa et al 9914 X 3,679,658 7/1972 Yuch et al 99l29 X JOSEPH M. GOLIAN, Primary Examiner US. Cl. X.R. 426--342 

